[Gvsig_english] Editing and other stuff

[Philippe Kruschitz]

Hi,

I'm currently testing gvSIG (1.1) within a project where we have to digitize a road network. As I use extensively the editing tools, I try to note the problems and their possible cause along the way.

As of now, I have noticed two smaller problems and a major one.


1.

The first one is not very probable and in fact, I found out about it accidentally. When editing an arc in a line shape and trying to close it to a circle by snapping the last point to the first one, gvSIG systematically crashes. This is obviously not a major problem, as there is an other (better) tool to draw circles.


2.

The second one is in my opinion a minor bug. It happened to me a couple of times during work. I noticed it first when I looked at the incredible extent my roads layer suddenly had after an edit session. A quick look in the attribute table showed some features that wouldn't appear on the screen when selected. "Zoom to selection" would bring me to the origin (0,0). It became evident that "null shapes" (shapes without geometric data) were created while editing. I searched for the possible cause and finally reproduced the error.

If you want to try it, it's pretty easy, just follow these steps:

- Create a new "line" layer
- Draw a polyline and "Terminate" or "Close" it. It should now appear in the attribute table.
- Now start a new line, but don't finish it. Instead of inserting the next point/vertice, simply right-click on the layer in the ToC, select "Finish Edition" and save the changes.
- Right-click again on the layer, "Start edition" and "Insert a polyline". The line you started in the last edit session should now reappear.
- Simply right-click in the view and you should notice that the usual drop-down menu isn't available (Internal arc, Close polyline, Terminate, Cancel), but only the "Cancel" option.
- Hitting [Enter] will make the line disappear, but a new entry has been created in the table.


With multipoints, polygons or normal lines, everything works fine. In the case of polylines, gvSIG obviously doesn't delete the null shape created by the "Insert a polyline" command. The problem lies in the fact that it's possible for the user to continue to draw a line (or polygon) created in the last edit session. I think this option should not even exist, as finishing an edit session should be definitive. In this case gvSIG kind of carries the "work in progress".


3.

Impossibility to use the snapping functions with the current digitized features considerably slows down the whole digitizing process. The view has to be loaded again, which makes the feature available for snapping. The user has to switch to another function of the software (pan, zoom or activate another layer for example) to be able to snap to the just-created feature. That is the problem that nerves me the most, as I can't snap my secondary road to the highway I just digitized without loading the whole thing again......




Apart from that, I have to say that I'm pretty impressed with the software itself. It's definitely a great open-source GIS and well worth the try. Continue the good work!




Best regards,


Philippe Kruschitz

Geography student at University Innsbruck currently working at GRID-IT.



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